Performance of Al2O3/TiC mixed ceramic inserts coated with TiAlSiN, WC/C and DLC thin solid films during hard turning of AISI 52100 steel

The present work evaluates the turning performance of alumina (Al2O3) and titanium carbide (TiC) based mixed ceramic cutting inserts with TiAlSiN, WC/C and DLC thin-film depositions during machining of AISI 52100 steel hardened to 55 ± 2 HRC hardness. Based on the generated machining forces, coefficient of friction, geometrical characteristics of the chips, and tool wear, a comparative analysis of the performance of uncoated and coated cutting tools was carried out. The machining outcomes were interpreted in relation to the adhesion strength of coating with the substrate, surface roughness and hardness of the top surface of the coatings. It was observed that the reduction of friction and machining forces accounted to lower localized strain along the shear plane leading to lower deformation of the chips. The TiAlSiN coating exhibited superior wear-resistance at the highest cutting speed when compared to DLC and WC/C coatings owing to its higher hardness and higher coating/substrate adhesion strength. However, the DLC and WC/C coatings, although softer, accounted to significant reduction of machining forces due to their self-lubricating properties.This work is sponsored by FEDER National funds FCT under the projects: SMARTLUB “Smart self-lubricant coatings with controlled release of the lubricious agent for high temperature applications.” (ref. “POCI-01-0145-FEDER-031807”), MCTool21 “Manufacturing of cutting tools for the 21st century: from nano-scale material design to numerical process simulation” (ref.: “POCI-01-0247-FEDER-045940”) and CEMMPRE ref. “UIDB/ 00285/2020”.info:eu-repo/semantics/publishedVersio

Condition Examine And Flaw Determination In Induction Motor- An Exploration

Induction motor notably three phase induction motor plays dynamic role in the industry due to their advantages over other electrical motors. Therefore, there is an extreme demand for their intense and secure operation. If any fault and failures occur in the motor it can lead to uncontrolled downtimes and generate prominent losses in terms of revenue and maintenance. Therefore, premature fault detection is needed for the indemnity of the motor. In the current scheme, the condition examine of the induction motor are increasing due to its potential to diminish operating costs, enhance the intense of operation and enhance service to the customers. The condition examine of induction motor is an emerging technology for online determination of incipient flaws. The on-line condition examine involves taking measurements on a machine while it is in operating conditions in order to determination of flaws with the aim of diminishing both unexpected flaws and maintenance costs. In the present paper, a comprehensive contemplate of induction machine flaws, diagnostic mechanism and future aspects in the condition examine of induction motor has been discussed

Effect of Surface Modifications on the Hard Turning Performance of Al2O3/TiCN Mixed Ceramic Cutting Tools

Hard turning process involves machining of materials of very high hardness, and thus, the process is associated with high machining forces resulting in the generation of a large amount of heat. The prevailing machining conditions during hard turning cause high tool wear. Thus, various surface modification techniques have been adopted to reduce the friction during the hard turning process resulting in the reduction of tool wear and thereby, increasing the cutting tool durability. Further, the alumina based mixed ceramic cutting tools are gaining popularity during hard turning process due to their economic nature as well as superior chemical and thermal stability. In this context, the present work focuses on investigating the effect of surface modifications mainly surface coatings and texturing on machining performance of Al2O3/TiCN based mixed ceramic cutting tools during turning of hardened AISI 52100 steel having 62 HRC hardness under dry cutting environment. The present work involves a total of five stages of investigation. Initially, the effect of coating thickness of mono-layered AlCrN and multi-layered AlTiN/TiN coatings have been investigated during the first and the second stages respectively from which it was revealed that the coating thickness significantly impacts the hard turning performance of Al2O3/TiCN based mixed ceramic cutting tool with 3 μm coating thickness for AlCrN and 4 μm coating thickness for AlTiN based coating exhibiting the best machining performance. These results have also been validated using 3D finite element numerical simulation performed with the help of Deform 3D software. The chip thickness, chip width and coefficient of friction increased with the increase in coating thickness. However, the performance of coated tools is more dependent on the coating/substrate adhesion strength of the coatings with better adhesion corresponding to superior machining performance. The third stage compares the performance of mono-layered AlCrN and multi-layered AlTiN/TiN PVD coatings of optimum thickness as obtained in the first two stages of investigation. The performance of the cutting tools was evaluated by tool wear and correlated in terms of material’s build-up at the tool-chip interface, friction, chip sliding velocity and cutting zone temperature. The results revealed increment of material’s build-up with feed rate whereas it decreased with the increase of cutting speed and chip sliding velocity. The sliding velocity increased with the increase of cutting speed resulting in lower contact time between the tool and the chip, and thus, the adhesion reduced with an increment of cutting speed. On the other hand, an increase of contact area in combination with higher cutting zone temperature and lower sliding velocities resulted in an increase of material’s build-up with feed rate. AlTiN coated cutting tools exhibited superior anti-oxidation, anti-adhesion and antiabrasive properties as compared to AlCrN coated and uncoated cutting tools. However, the AlCrN coating exhibited superior machining behaviour at higher cutting speeds indicating the suitability of the coating at elevated machining speeds. The fourth stage compares the machining performance of coatings deposited by cathodic arc evaporation (CAE) and DC reactive magnetron sputtering (DCRMS) process with different structures and deposition layers. Mono-layered AlCrN and multi-layered AlTiN were deposited using CAE process whereas nano-structured TiAlSiN/TiSiN/TiAlN coating was deposited using DCRMS process. The coated tools resulted in improved machining performance when compared to uncoated cutting tool. The CAE process resulted in surface defects like droplets and pores whereas the sputtering process generated droplet free surface that helped in superior performance of TiAlSiN/TiSiN/TiAlN coating when compared with AlTiN and AlCrN coatings. Moreover, nanostructure in TiAlSiN/TiSiN/TiAlN coating prevented coating flaking or peeling and ensured superior anti-abrasive behaviour due to its amorphous structure. In the last stage of investigation, micro scale textures were fabricated on the rake surface of Al2O3/TiCN composite ceramic cutting tools using Wire-EDM process. The performance of cutting tools was evaluated by tool-chip contact length, tool wear, machining forces, cutting temperature, frictional coefficient and chip morphology. Further, a 3D finite element model has been used to study the temperature and stress distribution in the cutting tools. Application of textures obstructing the chip flow direction resulted in uniform stress distribution, and higher groove sliding area ensured maximum reduction of machining forces, material adhesion, cutting and tool temperature. However, the textures parallel to the chip flow direction resulted in bending and curling of chips on the rake face causing increase of chiptool contact length and material adhesion resulting in increase of friction as compared to the tools with non-parallel textures. The textured tool with textures inclined at an angle to the chip flow direction exhibited the best machining performance as compared to other textured cutting tools. From the present work, it can be concluded that the surface modification techniques significantly improve the hard machining performance of Al2O3/TiCN mixed ceramic cutting tools

A 2D finite element approach for predicting the machining performance of nanolayered TiAlCrN coating on WC-Co cutting tool during dry turning of AISI 1045 steel

The hard coatings have proved very effective in industrial machining applications, and the development of new coatings relies more on simulations of the cutting process. In this regard, the present work investigates the machining performance of newly developed TiAlCrN multi-layered coating on tungsten carbide cutting tool during dry turning of AISI 1045 steel. A finite element model with damage evolution based on fracture energy was developed with the help of Abaqus/Explicit software. Later, the numerical results were validated by experimental measurements. The application of coating not only helped in the reduction of friction and tool temperatures at different cutting speeds but also affected the chip formation mechanism significantly. The secondary shear plane (SSP) was generated while machining with both uncoated and coated cutting tools. However, the SSP appeared only at higher cutting speeds in the case of the coated cutting tool. The proposed finite element model is able to predict the instability and formation of secondary serrated teeth with good accuracy.</p

Influence of Ag additions on the structure, mechanical properties and oxidation behaviour of CrAlNAg coatings deposited by sputtering

In this work, the influence of Ag additions into CrAlN coatings on the surface morphology, chemical composition, structure, hardness and oxidation behaviour was studied. Increasing the Ag content decreased the size of the morphological features and produced a more compact coatings. All coatings displayed a fcc structure typical of transition metal nitrides; the silver phase was indexed for the coatings with Ag concentration ≥8.6 at.%. XPS results confirmed that Ag existed as nanoclusters within the coating structure. A maximum hardness of around 23 GPa was observed for the 8.6 at.% of Ag. The decrease of the hardness with further increase in the Ag content was ascribed to the much softer character of this phase. The reference CrAlN coating displayed the best oxidation resistance and the lowest onset point of oxidation. The good oxidation resistance of this coating was attributed to the formation of a continuous and protective thin Cr2O3 layer on the top of the oxide layer. Ag additions degraded the oxidation resistance of the coatings, since the diffusion of Ag to the top surface of the oxide scale created extra paths for ions diffusion in the protective Cr-O layer. The formation of AgCrO2 phase in CrAlNAg9 coating, for the particular temperature of at 800 °C, was responsible for the low oxidation resistance of the coating as compared to the same coating oxidized at 900 °C. © 202

Improvement in Corrosion Performance of ECAPed AZ80/91 Mg Alloys Using SS316 HVOF Coating

Mg AZ80/91 alloys are highly popular due to their lightweight, high strength-to-weight ratio, and good machinability. However, their moderate mechanical properties and corrosion resistance have limited their use in the automotive, aerospace, and defense sectors. This study primarily aims to enhance the mechanical performance and corrosion resistance of Mg AZ80/91 alloys, making them more suitable for applications in the aerospace and automotive industries. Firstly, equal-channel angular pressing (ECAP) of Mg AZ80/91 alloys has been attempted to improve their mechanical properties. Secondly, a high-velocity oxy-fuel (HVOF) coating of SS316 was applied over the Mg AZ80/91 substrate to enhance its corrosion resistance. In the second step, an HVOF coating of SS316 is applied over the Mg AZ80/91 substrate for better corrosion resistance. The experimental findings demonstrate that the application of an SS316 coating on the ECAP-4P AZ80/91 Mg alloy substrate results in a uniform and dense layer with an average thickness of approximately 80 ± 5 µm. The HVOF-based SS316 coating on 4P-ECAP leads to a noteworthy enhancement in microhardness and a reduction in the corrosion rate, especially in a NaCl solution (3.5 wt.%). This improvement holds great promise for producing reliable, long-lasting, and resilient automotive, aerospace, and defense components. The application of an HVOF-based SS316 coating onto the AZ80 Mg alloy, which had not undergone ECAP treatment, led to a substantial enhancement in corrosion resistance. This resulted in a notable decrease in the corrosion current density, reducing it from 0.297 mA/cm2 to 0.10 µA/cm2

Assessment of eco-sustainability vis-à-vis zoo-technical attributes of soybean meal (SBM) replacement with varying levels of coated urea in Nellore sheep (Ovis aries).

The contemporary environmental-stewardship programmes primarily aimed at curbing the global warming potential by adopting a multidisciplinary approach. Manipulating the feeding strategies has great potential in reducing the environmental footprints of livestock production. This study intends to assess the effect of soybean meal (SBM) replacement with varying levels of coated urea (SRU) on both zoo-technical (nutrient digestibility, heat increment, and physio-biochemical parameters) and environmental attributes. The coated urea was used to replace the SBM at 0, 25, 50, and 75 percent levels. Eight adult rams (43.02 ± 0.76) maintained in a conventional shed were used in a replicated 4 x 4 Latin square design. Not all the physiological parameters viz. rectal temperature, pulse rate, and respiratory rate were affected (P>0.05)f by varying levels of SRU incorporation. The SRU fed animals had higher (P<0.05) crude protein digestibility compared to SBM fed animals; however, the replacements did not affect the nutrient digestibility coefficients of DM, OM, NFC, NDFap, ADF, and hemicellulose components. The SRU did not affect various biochemical parameters such as serum glucose, total protein, albumin, globulin, urea, creatinine, ALT, AST, Ca, P and T3, and T4 levels; however, post-prandial serum urea N (SUN) values showed a diurnal quadratic pattern (P<0.05) with a dose-dependent relationship. Further, the SBM replacements had no effect on the calcium excretion, while the SRU incorporation decreased the faecal phosphorous content, thereby abating the eutrophication phenomenon. Although the SBM replacements did not affect in vivo water variables and faecal solid fractions, they managed to decrease the land and virtual water requirement along with global warming potential (GWP) of the entire trial. The GWP-perceptual map unveils the fact that replacement of conventional feed ingredients with NPN compounds aids in eco-friendly livestock production. Further, the conjectural analysis of the carbon footprint methodology revealed that agricultural by-products consideration could cause a huge increase in the GWP share of feed consumed, thus compelling the importance of research pertaining to feed production perspective as equal as ruminal methane amelioration